Background: B-mode ultrasound studies indicate that hyperhomocysteinemia is associated with preclinical structural and functional arterial abnormalities. This study was designed to evaluate the effect of elevated plasma homocysteine levels on coronary flow reserve (CFR).
Methods: A total of 20 healthy subjects aged 41 +/- 7 years were studied on 2 separate days, a week apart, before and after methionine load (100 mg/kg of body weight) or placebo in a double-blind crossover study. At each visit, homocysteine levels were measured by high performance liquid chromatography and CFR was determined by transthoracic Doppler echocardiography.
Results: After methionine load, plasma homocysteine increased from 10.7 +/- 2.8 mumol/L to 30.4 +/- 5.1 mumol/L ( P < .0001) and CFR decreased from 3.0 +/- 0.4 to 2.3 +/- 0.3 ( P < .001). CFR was inversely related to postload homocysteine levels ( r = -0.21, P = .02). After placebo, there was no change in CFR.
Conclusion: In asymptomatic adults, acute hyperhomocysteinemia is associated with a significant reduction in CFR.